Optical waveguide, display device and display method thereof

Abstract

The invention discloses an optical waveguide, a display device and a display method thereof. The optical waveguide comprises an optical waveguide main body; the coupling-in area is used for coupling the first polarized light into the optical waveguide main body; the coupling-out area is arranged on one side of the optical waveguide main body and is used for coupling out the first polarized light in the optical waveguide main body; the liquid crystal layer is arranged on the other side of the optical waveguide main body, and the liquid crystal layer and the coupling-out area are oppositely arranged; wherein the liquid crystal layer comprises a plurality of liquid crystal units, and each liquid crystal unit can be switched between a first state and a second state. According to the display device, by controlling coupling-out of the light in the coupling-out area and transmission of the light in the liquid crystal layer, content display of a wearer is achieved through the coupling-out area, content display of the external environment is achieved through the liquid crystal layer, the user experience is improved, and bidirectional interaction between people and the environment is achieved.

Description

Technical Field

[0001] The present invention relates to the field of optical display technology, and in particular to an optical waveguide, a display device and a display method thereof. Background Art

[0002] The rapid development of augmented reality (AR) technology has enabled AR glasses to gradually enter the market from laboratory prototypes and become a representative device for innovative interaction. By superimposing virtual information on real scenes, AR glasses bring users a new audio-visual experience and are widely used in entertainment, navigation, education, and industrial guidance. With the popularization of technology, the functional requirements of AR glasses are gradually diversified. One of the emerging requirements is how to display specific information on the outside of the glasses to the external environment, such as "Do Not Disturb" and "Working" prompts, so as to achieve two-way interaction between people and the environment.

[0003] Although traditional optical waveguide and micro-projection technologies are mature, their design focus is on displaying content in the wearer's field of view, and it is difficult to directly accommodate the needs of outward-facing display. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an optical waveguide, a display device and a display method thereof to solve the technical problem that although traditional optical waveguide and micro-projection technologies are mature, their design focus is on displaying content in the wearer's field of view and it is difficult to directly accommodate the needs of outward display.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides an optical waveguide, comprising: an optical waveguide body; an incoupling region for coupling a first polarized light into the optical waveguide body; an outcoupling region, arranged on one side of the optical waveguide body, for coupling the first polarized light out of the optical waveguide body; a liquid crystal layer, arranged on the other side of the optical waveguide body, and the liquid crystal layer is arranged opposite to the outcoupling region; wherein the liquid crystal layer comprises a plurality of liquid crystal units, each of which can be switched between a first state and a second state, the first polarized light can pass through the liquid crystal unit in the first state, and the first polarized light cannot pass through the liquid crystal unit in the second state.

[0007] The projection of the liquid crystal layer onto the optical waveguide body covers the projection of the outcoupling region onto the optical waveguide body.

[0008] Wherein, it also includes a turning area arranged on the optical waveguide body, and the turning area is arranged between the coupling-in area and the coupling-out area.

[0009] Wherein, the outcoupling region is provided with a relief grating and / or a volume holographic grating.

[0010] In a second aspect, the present invention provides a display device, comprising an optical waveguide as in the first aspect, and a light source device and a control device, wherein the light source device is used to project a first polarized light onto the coupling-in region, and the control device is used to control at least part of the liquid crystal units to switch from a second state to a first state, so that the first polarized light passes through the liquid crystal units in the first state in the liquid crystal layer, thereby forming an image.

[0011] The light source device includes a first optical machine for directly emitting the first polarized light, or the light source device includes a second optical machine for emitting natural light and a polarizer configured on the second optical machine, wherein the polarizer is used to receive the natural light emitted by the second optical machine and output it as the first polarized light.

[0012] Wherein, it also includes a mirror frame and temples, the optical waveguide and the light source device are installed on the mirror frame, and the control device is installed on the mirror frame and / or the temples.

[0013] In a third aspect, the present invention provides a display method, applied to the display device of the second aspect, comprising:

[0014] Controlling the light source device to emit a first polarized light;

[0015] receiving a control signal, and determining a target liquid crystal unit according to the control signal;

[0016] The target liquid crystal unit is controlled to switch from the second state to the first state, so that the first polarized light passes through the target liquid crystal unit, thereby forming an image.

[0017] The receiving of the control signal and determining the target liquid crystal unit according to the control signal comprises:

[0018] Analyze and obtain display content information in the control signal, divide the liquid crystal layer into a display area and a non-display area according to the display content information, and determine the liquid crystal unit in the display area as a target liquid crystal unit.

[0019] The step of controlling the target liquid crystal unit to switch from the second state to the first state so that the first polarized light passes through the target liquid crystal unit to form an image includes:

[0020] Analyze and obtain display color information in the control signal, and obtain the duty ratio of the preset color light in the light emitted by the light source device;

[0021] According to the duty cycle of the preset color light in the light emitted by the light source device, the target liquid crystal unit is controlled to switch to a first state when the light source device emits the preset color light, and to switch to a second state when the light source device emits other color lights.

[0022] The optical waveguide of the present invention controls the coupling out of the light in the coupling out region and the transmission in the liquid crystal layer, so that the coupling out region realizes the display of the content to the wearer, and the liquid crystal layer realizes the display of the content to the external environment, thereby improving the user experience and realizing the two-way interaction between people and the environment. At the same time, the design of the present invention effectively utilizes the light leakage in the coupling out region, which not only can realize the two-way interaction between people and the environment, but also prevents the light leakage in the coupling out region from displaying the image on the user side to the outside world, further protecting the user's privacy and preventing the outside world from seeing the content that the user is watching.

[0023] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the following preferred embodiments are specifically cited and described in detail as follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a first structural schematic diagram of an optical waveguide according to an embodiment of the present invention;

[0025] Figure 2 It is a second structural schematic diagram of the optical waveguide according to an embodiment of the present invention;

[0026] Figure 3 is a third structural schematic diagram of an optical waveguide according to an embodiment of the present invention;

[0027] Figure 4 A first structural schematic diagram of a display device according to an embodiment of the present invention;

[0028] Figure 5 A second structural schematic diagram of a display device according to an embodiment of the present invention;

[0029] Figure 6 A flow chart showing a method according to an embodiment of the present invention;

[0030] Figure 7 A first sub-flow chart showing a method according to an embodiment of the present invention;

[0031] Figure 8 This is a second sub-flowchart of the method according to an embodiment of the present invention.

[0032] Description of main symbols:

[0033] 10. Optical waveguide body; 20. Incoupling region; 30. Outcoupling region; 40. Liquid crystal layer; 50. First optical machine; 60. Second optical machine; 61. Polarizer. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0036] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “resin”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, etc., indicating orientations or positional relationships are orientations or positional relationships based on the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0038] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be connected, detachably connected, or integrated; it can be mechanically connected or electrically connected; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0040] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0041] See also Figure 1 and Figure 2 , Figure 1 is a first structural schematic diagram of an optical waveguide according to an embodiment of the present invention, Figure 2 The second structural schematic diagram of the optical waveguide of the embodiment of the present invention. The embodiment of the present invention provides an optical waveguide, comprising: an optical waveguide body 10; a coupling-in region 20, for coupling a first polarized light into the optical waveguide body 10; a coupling-out region 30, arranged on one side of the optical waveguide body 10, for coupling out the first polarized light in the optical waveguide body 10; a liquid crystal layer 40, arranged on the other side of the optical waveguide body 10, and the liquid crystal layer 40 is arranged opposite to the coupling-out region 30; wherein the liquid crystal layer 40 comprises a plurality of liquid crystal units, each of which can be switched between a first state and a second state, the first polarized light can pass through the liquid crystal unit in the first state, and the first polarized light cannot pass through the liquid crystal unit in the second state. wherein the switching between the first state and the second state of the liquid crystal unit is achieved by changing the electric field state of the liquid crystal unit, thereby changing the arrangement of the liquid crystal molecules, and then controlling the transmission of light. Specifically, when no electric field is applied, the liquid crystal molecules are usually arranged in a twisted nematic arrangement or a vertical arrangement; when an electric field is applied, the liquid crystal molecules will rearrange to adapt to the direction of the electric field. When light passes through the liquid crystal unit, the arrangement of the liquid crystal molecules will affect the polarization state of the light. If the arrangement of the liquid crystal molecules is consistent with the polarization direction of the light, the light can pass smoothly; if the arrangement is inconsistent, the light will be blocked. Therefore, by changing the intensity and direction of the electric field, the arrangement of the liquid crystal molecules can be controlled, thereby achieving control of the light transmittance. This control method allows the liquid crystal layer 40 to dynamically adjust its light transmittance state, thereby achieving the function of the liquid crystal unit only allowing the first polarized light to pass in the first state.

[0042] It can be understood that the light is coupled into the optical waveguide body 10 through the coupling-in region 20, and propagates in the optical waveguide body 10 to the coupling-out region 30 and the liquid crystal layer 40, forming a first image displayed to the wearer at the coupling-out region 30, and passing through the liquid crystal unit in the first state at the liquid crystal layer 40 to form a second image displayed to the external environment. Specifically, the first polarized light is coupled into the optical waveguide body 10 through the coupling-in region 20, and the first polarized light propagates through multiple total reflections in the optical waveguide body 10, and finally reaches the coupling-out region 30 and the liquid crystal layer 40. At the coupling-out region 30, the first polarized light is coupled out to form a first image for the user to watch; at the liquid crystal layer 40, the first polarized light is transmitted to form a second image for the external environment to watch. By setting the liquid crystal layer 40 on the other side of the optical waveguide body 10, the outward display function of the optical waveguide is realized, and the user experience is improved. It should be explained that due to the characteristics of grating diffraction, part of the first polarized light will be coupled out from the coupling-out region 30 to form the first image, and part of the first polarized light will propagate toward the liquid crystal layer 40 to form the second image. It is worth mentioning that in the prior art, light leakage in the out-coupling area 30 will display the image on the user side to the outside world, resulting in exposure of the user's privacy. The design of the present invention can effectively utilize the light leakage in the out-coupling area, avoiding the light leakage in the out-coupling area 30 from displaying the image on the user side to the outside world, further protecting the user's privacy and preventing the outside world from seeing what the user is watching.

[0043] It is understandable that in order to realize pixelation control of the liquid crystal layer 40 so that specific images or texts can be accurately displayed, the present embodiment divides the liquid crystal layer 40 into a plurality of liquid crystal units, each of which can independently control its light transmission state to switch between the first state and the second state, thereby realizing fine control of the displayed content. This design enables the liquid crystal layer 40 to flexibly display various information to meet the needs of different scenarios, such as prompts such as "Do Not Disturb" and "Working", so as to realize two-way interaction between people and the environment.

[0044] In some embodiments, the projection of the out-coupling region 30 onto the optical waveguide body 10 covers the projection of the liquid crystal layer 40 onto the optical waveguide body 10 , so that the liquid crystal layer 40 can maximize the use of the out-coupling light from the out-coupling region 30 , reduce light loss, and improve the brightness and clarity of the display effect of the liquid crystal layer 40 .

[0045] In some embodiments, Figure 3As shown, the optical waveguide further includes a turning region 50 disposed in the optical waveguide body 10, and the turning region 50 is disposed between the coupling-in region 20 and the coupling-out region 30, and is used to expand the display range of the first polarized light coupling-out image. Preferably, the optical waveguide is a diffraction optical waveguide. It should be explained that through the image expansion function of the turning region, the size of the eye box can be significantly increased, which enables the optical waveguide of this embodiment to adapt to more people, improve mechanical tolerance, and promote the realization of consumer-grade products.

[0046] In some embodiments, the out-coupling region 30 is provided with a relief grating and / or a volume holographic grating. It should be explained that the present application does not limit the structure of the coupling-in region 20 and the turning region 50, and may include a reflector, a prism, a relief grating, a volume holographic grating, etc. In order to utilize the optical waveguide with light leakage characteristics, the present application allows the out-coupling light of the out-coupling region 30 to propagate to the liquid crystal layer 40, and the structure of the out-coupling region 30 generally includes a relief grating and / or a volume holographic grating. It can be understood that due to the high diffraction efficiency of the relief grating, it can effectively guide the light out of the waveguide at a specific angle and wavelength, thereby achieving a light leakage effect; and when the volume holographic grating is used as a coupling element, its internal refractive index modulation can form a specific diffraction effect in the optical waveguide. When the light propagates in the waveguide, the volume holographic grating can couple part of the light to the outside to achieve light leakage.

[0047] See also Figure 4 and Figure 5 , Figure 4 is a first structural schematic diagram of a display device according to an embodiment of the present invention, Figure 5 The second structural schematic diagram of the display device of the embodiment of the present invention. The present invention provides a display device, comprising the above optical waveguide, a light source device and a control device, the light source device is used to project the first polarized light to the coupling region 20, and the control device is used to control at least part of the liquid crystal units to switch from the second state to the first state, so that the first polarized light passes through the liquid crystal units in the first state in the liquid crystal layer 40, thereby forming an image. Optionally, the control device includes a central processing unit (CPU) or a micro control unit (MCU) or a digital signal processor (DSP), etc.

[0048] It can be understood that the control device sends instructions to a specific area of ​​the liquid crystal layer 40 according to the preset display content. After receiving the instructions, the liquid crystal unit in this area switches to the first state or the second state. The first polarized light passes through the liquid crystal unit in the first state to form a second image, while the opaque liquid crystal unit blocks the light to form a non-display area of ​​the background.

[0049] In some embodiments, taking the first polarized light as P polarized light (P light) as an example, the liquid crystal unit in the first state is a P light-transmitting S polarized light (S light), and the liquid crystal unit in the second state is a S light-transmitting P light. Therefore, in the second state, the P light propagated from the coupling region 20 to the liquid crystal unit will not be able to pass through the liquid crystal unit. The user can adjust the state of the liquid crystal unit through host computer control or voice input control. For example, when the user wants the device to display "I am AR", the user can input instructions and then control the state of the liquid crystal unit in a specific area of ​​the liquid crystal layer 40 through the control device, so that these liquid crystal units are transparent to P light and block S light, while other liquid crystal units remain in the second state, thereby realizing the function of displaying specific content to the outside. It should be explained that P light is light whose polarization direction is parallel to the incident plane, and S light is light whose polarization direction is perpendicular to the incident plane. This embodiment does not limit the polarization state of the first polarized light.

[0050] In an achievable embodiment, when a user wishes to display specific content to the outside world through a display device (such as AR glasses), the user can manually input it through a host computer (such as a computer, tablet or mobile phone) that is compatible with the display device of this application. For example, in an office environment, a user wearing AR glasses wants to display a "Do Not Disturb" prompt to colleagues. The user can open the corresponding application through a connected host computer (such as a laptop), enter "Do Not Disturb" and confirm; after receiving the input, the control device controls the liquid crystal unit of the corresponding area of ​​the liquid crystal layer 40 to switch to the first state and display the "Do Not Disturb" message.

[0051] In another achievable embodiment, when the user wishes to display specific content to the outside world through a display device (such as AR glasses), the user can also control the display content of the liquid crystal layer 40 by voice input. In this embodiment, the control device should also include a language control module that can recognize the user's voice command and convert it into corresponding display content. For example, when a user is doing a certain job and is operating a tool with his hands and cannot use a manual input device, the user can say "display Do Not Disturb" through a voice command. After the language control module recognizes the command, it will automatically control the liquid crystal unit in the corresponding area of ​​the liquid crystal layer 40 to switch to the first state and display the "Do Not Disturb" message.

[0052] It is understandable that for users wearing display devices (such as AR glasses), the content displayed in their field of vision is normal, that is, the user still sees the surrounding environment and the augmented reality information provided by the AR glasses, and the content displayed in their field of vision will not be disturbed by the liquid crystal layer. When the user controls the liquid crystal layer to display content such as "Do Not Disturb" through the host computer or voice input, outsiders observing the user can see the "Do Not Disturb" displayed on the AR glasses, thereby understanding the information that the user does not want to be disturbed.

[0053] In some embodiments, the light source device includes a first optical machine 50 for directly emitting a first polarized light, or the light source device includes a second optical machine 60 for emitting natural light and a polarizer 61 configured on the second optical machine 60, the polarizer 61 being used to receive the natural light emitted by the second optical machine 60 and output it as a first polarized light.

[0054] It can be understood that the light emitted by the first optical machine 50 is the first polarized light, and the light emitted by the first optical machine 50 can match the transmitted polarized light (i.e., the first polarized light) when the liquid crystal unit is in the first state. The second optical machine 60 sets a polarizer 61 below the light exit hole so that the light entering the waveguide is the first polarized light. The function of the polarizer 61 is to convert natural light or non-polarized light into the first polarized light to ensure that it matches the transmitted polarized light (i.e., the first polarized light) when the liquid crystal unit is in the first state. Optionally, the first optical machine 50 can be an LCOS optical machine or a fiber laser. The LCOS optical machine is a reflective display device based on liquid crystal technology. It can utilize the birefringence characteristics of liquid crystal molecules to modulate the amplitude or phase of the incident light by regulating the polarization state of light to ensure that its output light is the first polarized light; the fiber laser achieves particle number inversion by doping rare earth ions in the optical fiber to generate laser, and the first polarized light output can be achieved by using polarization-maintaining optical fiber. Optionally, the second optical machine 60 can be a DLP optical machine or an LBS optical machine.

[0055] In some embodiments, the display device may be an AR glasses, which includes a frame and temples, the optical waveguide and the light source device are mounted on the frame, and the control device is mounted on the frame and / or temples. Specifically, the outcoupling region 30 of the optical waveguide is arranged on the side facing the wearer's eyes after the AR glasses are worn, and the liquid crystal layer 40 is arranged on the side facing outward after the AR glasses are worn. Optionally, the coupling region 20 and the outcoupling region 30 are located on the same side of the optical waveguide body 10.

[0056] See also Figure 6 , Figure 6 This is a flow chart of a display method according to an embodiment of the present invention. The present invention provides a display method, which is applied to the display device as described above, and includes steps S100-S300:

[0057] S100, controlling the light source device to emit a first polarized light;

[0058] S200, receiving a control signal, and determining a target liquid crystal unit according to the control signal;

[0059] S300 , controlling the target liquid crystal unit to switch from the second state to the first state, so that the first polarized light passes through the target liquid crystal unit, thereby forming an image.

[0060] It is understandable that the liquid crystal layer is composed of a plurality of liquid crystal units, each of which can independently control its light transmission state. According to the second image preset by the user (such as "Do Not Disturb"), the control device will adjust the target liquid crystal unit in the liquid crystal layer to the first state, and the other liquid crystal units to the second state, so that light can only pass through the target liquid crystal unit to form the preset second image. Among them, the target liquid crystal unit refers to the liquid crystal unit in the area of ​​the liquid crystal layer where images or texts need to be displayed. These target liquid crystal units will be adjusted to the first state so that the first polarized light can pass through these areas to form the preset images or texts.

[0061] See also Figure 7 , Figure 7 This is a first sub-flow chart of the method shown in an embodiment of the present invention, wherein step S200 includes step S210:

[0062] S210 , dividing the liquid crystal layer into a display area and a non-display area according to the display content information, and determining a liquid crystal cell in the display area as a target liquid crystal cell.

[0063] It is understandable that the display content information may include images, text or other content that needs to be displayed. For example, if the second image preset by the user is "Do Not Disturb", the control device will recognize this display content information. The display area refers to the area in the liquid crystal layer where images or texts need to be displayed, and the non-display area is the area where images or texts do not need to be displayed. Specifically, the liquid crystal unit in the display area, that is, the target liquid crystal unit, needs to be switched to the first state; and the liquid crystal unit in the non-display area needs to be switched to the second state. For example, if the display content information is "Do Not Disturb", the control device will divide the area on the liquid crystal layer where the text "Do Not Disturb" is displayed as the display area, and other areas as non-display areas. The control device will send a corresponding control signal to switch the target liquid crystal unit to the first state and the liquid crystal unit in the non-display area to the second state, forming a preset second image (such as "Do Not Disturb").

[0064] See also Figure 8 , Figure 8 This is a second sub-flow chart of the method shown in an embodiment of the present invention, wherein step S300 includes steps S310-S320:

[0065] S310, analyzing and acquiring display color information in the control signal, and acquiring a duty cycle of a preset color light in light emitted by the light source device.

[0066] It should be explained that the duty cycle refers to the ratio of the time that the signal is at a high level (or valid state) to the entire cycle time in a periodic signal. In this embodiment, the duty cycle is used to describe the time proportion of the preset color light in the light emitted by the light source device. In some embodiments, the display color information in the control signal indicates the display of a red image, and the control device determines the duty cycle of the red light, that is, the time proportion of the red light in the light emitted by the light source device. In some embodiments, the preset color light can be red light, green light, blue light, or a single color light of other colors.

[0067] S320, according to the duty cycle of the preset color light in the light emitted by the light source device, controlling the target liquid crystal unit to switch to a first state when the light source device emits the preset color light, and to switch to a second state when the light source device emits other color lights.

[0068] It should be explained that other colored light refers to light of other colors except the preset colored light. It is understandable that, by using the duty ratio of the preset colored light in the light emitted by the light source device, the control device can control the time when the target liquid crystal unit is in the first state to coincide with the time when the light source device emits the preset colored light, thereby achieving the transmission of the preset colored light and making the second image displayed in the preset colored light, for example, forming a "Do Not Disturb" displayed in red, or a "Do Not Disturb" displayed in green, etc.

[0069] The above examples are only used to further illustrate the technical content of the present invention, so that readers can understand it more easily, but they do not mean that the implementation of the present invention is limited to this. Any technical extension or re-creation made according to the present invention is protected by the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. An optical waveguide, characterized in that: include: An optical waveguide body; A coupling-in region, used for coupling the first polarized light into the optical waveguide body; An outcoupling region, disposed on one side of the optical waveguide body, for outcoupling the first polarized light in the optical waveguide body; A liquid crystal layer is arranged on the other side of the optical waveguide body, and the liquid crystal layer is arranged opposite to the outcoupling region; The liquid crystal layer includes a plurality of liquid crystal units, each of which can be switched between a first state and a second state, the first polarized light can pass through the liquid crystal unit in the first state, and the first polarized light cannot pass through the liquid crystal unit in the second state.

2. An optical waveguide according to claim 1, characterized in that: The projection of the liquid crystal layer onto the optical waveguide body covers the projection of the outcoupling region onto the optical waveguide body.

3. An optical waveguide according to claim 1, characterized in that: The optical waveguide also includes a turning region disposed on the optical waveguide body, wherein the turning region is disposed between the coupling-in region and the coupling-out region.

4. An optical waveguide according to claim 1, characterized in that: The outcoupling region is provided with a relief grating and / or a volume holographic grating.

5. A display device, characterized in that: The optical waveguide comprises the optical waveguide according to any one of claims 1 to 3, and a light source device and a control device, wherein the light source device is used to project a first polarized light to the coupling-in region, and the control device is used to control at least part of the liquid crystal units to switch from a second state to a first state, so that the first polarized light passes through the liquid crystal units in the first state in the liquid crystal layer, thereby forming an image.

6. A display device according to claim 5, characterized in that: The light source device includes a first optical machine for directly emitting the first polarized light, or the light source device includes a second optical machine for emitting natural light and a polarizer configured on the second optical machine, the polarizer is used to receive the natural light emitted by the second optical machine and output it as the first polarized light.

7. A display device according to claim 5, characterized in that: It also includes a mirror frame and temples, the optical waveguide and the light source device are installed on the mirror frame, and the control device is installed on the mirror frame and / or the temples.

8. A display method, characterized in that: The display device according to any one of claims 5 to 7 comprises: Controlling the light source device to emit a first polarized light; receiving a control signal, and determining a target liquid crystal unit according to the control signal; The target liquid crystal unit is controlled to switch from the second state to the first state, so that the first polarized light passes through the target liquid crystal unit, thereby forming an image.

9. A display method according to claim 8, characterized in that: The receiving of the control signal and determining the target liquid crystal unit according to the control signal comprises: Analyze and obtain display content information in the control signal, divide the liquid crystal layer into a display area and a non-display area according to the display content information, and determine the liquid crystal unit in the display area as a target liquid crystal unit.

10. A display method according to claim 9, characterized in that: The controlling the target liquid crystal unit to switch from the second state to the first state so that the first polarized light passes through the target liquid crystal unit to form an image includes: Analyze and obtain display color information in the control signal, and obtain the duty ratio of the preset color light in the light emitted by the light source device; According to the duty cycle of the preset color light in the light emitted by the light source device, the target liquid crystal unit is controlled to switch to a first state when the light source device emits the preset color light, and to switch to a second state when the light source device emits other color lights.

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